Lead frame and light receiving module comprising it

ABSTRACT

On a leadframe on which to fix a photodetector element, an element mount frame and a fitting frame are laid with a gap left in between. A shielding frame for electromagnetically shielding the photodetector element is tied, via a tying portion, not to the element mount frame but to the fitting frame. Bending the tying portion brings it into a state in which it covers the photodetector element, but the stress resulting from this bending of the tying portion is shut off by the gap so as not to spread to the element mount frame. On the element mount frame, a circuit element for processing the signal from the photodetector element also is fixed.

TECHNICAL FIELD

The present invention relates to a leadframe, and to a photodetectormodule provided therewith.

BACKGROUND ART

There have been developed a variety of appliances that can be remotelycontrolled. Many such appliances exchange remote-control signals in theform of optical signals of, for example, infrared rays. A photodetectormodule for receiving optical signals handles faint signals, and istherefore susceptible to electromagnetic noise. A well-known approach toshut off the influence of electromagnetic noise from a photodetectormodule is to use a shielding plate. How a shielding plate is used isdisclosed, for example, in Japanese Patent Application Laid-Open No.H10-242487. Japanese Patent Application Laid-Open No. H10-242487discloses the following structure. A frame on which a photodetectorelement is mounted is tied, via a tying portion with a smaller width, toa shielding plate. The tying portion is bent so that the shielding platecovers the photodetector element, and the shielding plate is kept at theground potential so as to shut off electromagnetic noise.

In the structure disclosed in Japanese Patent Application Laid-Open No.H10-242487, the shielding plate is fixed to the photodetector elementmount frame. Thus, when the tying portion is bent, the resulting stressis likely to spread to the photodetector element mount frame. Althoughthe tying portion has a groove, opening, or the like formed therein soas to have as small a width as possible, still the bending stressspreads to the photodetector element mount frame. If this stress deformsthe photodetector element mount frame, it acts as a factor that brings achange in the angle of the photodetector element. A deviation in theangle of the photodetector element from the design value leads todegraded photodetective characteristics. On the other hand, the heatdissipated from the photodetector element itself and from the circuitelements that process the signals therefrom also produces stress betweenthe photodetector element mount frame and the shielding plate. Thisstress may cause cracks in the resin for molding.

DISCLOSURE OF THE INVENTION

In view of the above problems, an object of the present invention is toprovide, for a leadframe and for a photodetector module providedtherewith, a structure in which unnecessary stress is unlikely to spreadto an element mount frame when a shielding frame for covering theelement mount frame is bent at a tying portion.

To achieve the above object, according to the present invention, aleadframe and a photodetector module provided therewith are given one ofthe following structures.

In a first structure, a leadframe is provided with an element mountframe, a fitting frame that is laid beside the element mount frame witha gap left in between, and a shielding frame that is tied via a tyingportion to the fitting frame and that can be brought into such a stateas to cover the element mount frame. With this structure, when the tyingportion is bent, the resulting stress spreads to the fitting frame, butis less likely to spread to the element mount frame thanks to the gapleft between it and the fitting frame. This prevents deformation of theelement mount frame, thus prevents a change in the angle of thephotodetector element, and thus prevents deterioration of thephotodetective characteristics.

In a second structure, in the leadframe structured as described above,the tying portion is provided at both ends of the gap. With thisstructure, the leadframe has increased mechanical strength. Moreover,the trouble of connecting the element mount frame and the fitting frametogether by a wire can be saved.

In a third structure, in the leadframe structured as described above,the element mount frame and the fitting frame are separate. With thisstructure, no part of the stress resulting from the bending of the tyingportion of the shielding frame spreads to the element mount frame. Thus,deformation of the element mount frame can be completely prevented.

In a fourth structure, in the leadframe structured as described above,the fitting frame is, in a portion thereof near the tying portion,shaped symmetrically about the tying portion. With this structure, thestress resulting from the bending of the tying portion is equallydistributed between both sides of the tying portion. That is, the stressnever concentrates in one side to eventually spread to the element mountframe.

In a fifth structure, a photodetector module is provided with aphotodetector element, an element mount frame on which the photodetectorelement is mounted, a fitting frame that is laid beside the elementmount frame with a gap left in between, a shielding frame that is tiedvia a tying portion to the fitting frame and that can be brought intosuch a state as to cover the element mount frame, and molding resin inwhich the element mount frame and the fitting frame are sealed. Withthis structure, when the tying portion is bent, the resulting stressspreads to the fitting frame, but is less likely to spread to theelement mount frame thanks to the gap left between it and the fittingframe. This prevents deformation of the element mount frame, thusprevents a change in the angle of the photodetector element, and thusprevents deterioration of the photodetective characteristics. Moreover,since the element mount frame and the fitting frame are sealed in themolding resin, the photodetector module has high mechanical strength,and is free from a change in the angle of the photodetector element.

In a sixth structure, in the photodetector module structured asdescribed above, the element mount frame and the shielding frame arekept at an equal potential. With this structure, the element mount framecan function as a grounding frame.

In a seventh structure, in the photodetector module structured asdescribed above, the element mount frame and the shielding frame arekept at different potentials. With this structure, the shielding frame,which is kept at a different potential, functions to shieldelectromagnetic noise.

In an eighth structure, in the photodetector module structured asdescribed above, a circuit element that processes a signal from thephotodetector element is mounted on the element mount frame. With thisstructure, the signal from the photodetector element can be processedunder the shield provided by the shielding frame. Thus, even a faintsignal can be processed without being influenced by electromagneticnoise.

In a ninth structure, in the photodetector module structured asdescribed above, the element mount frame and the gap have nearly equallengths. With this structure, unnecessary stress is unlikely to spreadto the element mount frame. This helps realize a photodetector modulewith good photodetective characteristics.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of the photodetector module of a firstembodiment of the invention.

FIG. 2 is a front view of the photodetector module of the firstembodiment.

FIG. 3 is a front view of the photodetector module of the firstembodiment, with the molding resin removed.

FIG. 4 is a side view of the photodetector module of the firstembodiment.

FIG. 5 is a bottom view of the photodetector module of the firstembodiment.

FIG. 6 is a plan view of the leadframe used in the photodetector moduleof the first embodiment.

FIG. 7 is a plan view of the leadframe used in the photodetector moduleof the first embodiment, showing a portion thereof corresponding to asingle photodetector module.

FIG. 8 is a plan view of the leadframe used in the photodetector moduleof the first embodiment, as observed at one stage in the course of theassembly thereof.

FIG. 9 is a plan view of the leadframe used in the photodetector moduleof the first embodiment, as observed at another stage, different fromthe one shown in FIG. 8, in the course of the assembly thereof.

FIG. 10 is a perspective view of the photodetector module of a secondembodiment of the invention.

FIG. 11 is a front view of the photodetector module of the secondembodiment.

FIG. 12 is a front view of the photodetector module of the secondembodiment, with the molding resin removed.

FIG. 13 is a side view of the photodetector module of the secondembodiment.

FIG. 14 is a bottom view of the photodetector module of the secondembodiment.

FIG. 15 is a plan view of the leadframe used in the photodetector moduleof the second embodiment.

FIG. 16 is a plan view of the leadframe used in the photodetector moduleof the second embodiment, showing a portion thereof corresponding to asingle photodetector module.

FIG. 17 is a plan view of the leadframe used in the photodetector moduleof the second embodiment, as observed at one stage in the course of theassembly thereof.

FIG. 18 is a plan view of the leadframe used in the photodetector moduleof the second embodiment, as observed at another stage, different fromthe one shown in FIG. 17, in the course of the assembly thereof.

FIG. 19 is a plan view of the leadframe used in the photodetector moduleof a third embodiment of the invention, as observed at one stage in thecourse of the assembly thereof.

FIG. 20 is a plan view of the leadframe used in the photodetector moduleof a fourth embodiment of the invention, as observed at one stage in thecourse of the assembly thereof.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

FIGS. 1 to 5 show the photodetector module of a first embodiment of theinvention. FIG. 1 is a perspective view, FIG. 2 is a front view, FIG. 3is a front view with the molding resin removed, FIG. 4 is a side view,and FIG. 5 is a bottom view.

A photodetector module M1 is used in television monitors, airconditioners, and other appliances to receive remote control signals(infrared signals). The photodetector module M1 has a photodetectorelement 1 and, as a circuit for processing the signal therefrom, anintegrated circuit 2 (hereinafter abbreviated to “IC 2”) both sealed ina rectangular block of molding resin 3.

From the rear face of the molding resin 3 protrude four leads L1 to L4.The leads L1 to L4 are formed by bending parts of a leadframe F1, whichwill be described later.

The photodetector module M1 has the following structure. In a partialregion on a metal leadframe F1, the photodetector element 1 and the IC 2for processing the signal therefrom are mounted beside each other, andthese are sealed into a single unit with the molding resin 3. Themolding resin 3 is, at the front face thereof, about 10 mm high by about6 mm wide, and has, on the front face thereof, a condenser lens 4 formedintegrally therewith.

Next, with reference to the FIGS. 6 to 9, which show the leadframe, thestructure of the photodetector module M1 will be described along withthe fabrication procedure thereof. FIG. 6 is a plan view of theleadframe, FIG. 7 is a plan view of the leadframe showing a portionthereof corresponding to a single photodetector module, FIG. 8 is a planview of the leadframe as observed at one stage in the course of theassembly thereof, and FIG. 9 is a plan view of the leadframe as observedat another stage, different from the one shown in FIG. 8, in the courseof the assembly thereof.

First, as partially shown in FIG. 6, a leadframe FF is prepared throughpunching of thin sheet metal. FIG. 7 shows the shape of the leadframe F1that is used in a single photodetector module. The leadframe FF is anaggregate of a plurality of leadframes F1 that are tied together by tiebars B, each leadframe F1 shaped as shown in FIG. 7 and corresponding toa single photodetector module.

As shown in FIGS. 3 and 7, along one of the longer sides of the moldingresin 3 extends an elongate fitting frame 8, and from both ends thereofprotrude the leads L1 and L2. The leads L1 and L2 are used forconnection to the ground potential (GND), and thus the fitting frame 8functions as a grounding frame.

An element mount frame 9, which has an element mount region thereon andhas a comparatively large area, is laid parallel with the fitting frame8. The fitting frame 8 and the element mount frame 9 form part of a mainframe 7. In the main frame 7, between the fitting frame 8 and theelement mount frame 9, a gap 5 is formed in the shape of an elongategroove or cut. The element mount frame 9 is, at both ends thereof, tiedto both ends of the fitting frame 8 by tie bars 10, 16, and 17. In otherwords, a tying portion for tying the element mount frame 9 and thefitting frame 8 together is provided on both sides of the gap 5.

Along the other of the longer sides of the molding resin 3 extends anelongate power supply (Vcc) frame 11, and from one end thereof protrudesthe lead L3. Likewise, along the other of the longer sides of themolding resin 3 extends, aligned with the power supply (Vcc) frame 11, asignal output (Vout) frame 12, and from one end thereof protrudes thelead L4.

In a position symmetric with the element mount frame 9 about the fittingframe 8, a shielding frame 15 is formed that has a window 14 formedtherein and that has a comparatively large area. The shielding frame 15is tied, via a tying portion 13, to a middle portion of the fittingframe 8. The fitting frame 8 is, in a portion thereof near the tyingportion 13, shaped nearly symmetrically about the tying portion 13.Thus, as will be described later, when the tying portion 13 is bent, theresulting stress is equally distributed between both sides of the tyingportion 13. Between the fitting frame 8 and the shielding frame 15,except in the tying portion 13, an elongate cut 6 is formed to separatethe fitting frame 8 and the shielding frame 15 from each other. Thishelps give a smaller width to the tying portion 13, which functions asthe very portion that is bent.

Between the tying portion 13 and the element mount frame 9 is left thegap 5. The length of the gap 5 is greater than any of the width of thetying portion 13, the length of the cut 6, the length of the elementmount frame 9, and the length of the shielding frame 15. Here, all the“widths” and “lengths” mentioned are dimensions along the longer sidesof the molding resin 3.

The leads L1 and L3, which are adjacent along the shorter sides of themolding resin 3, are tied together by the tie bar 16. Likewise, theleads L2 and L4, which are adjacent along the shorter sides of themolding resin 3, are tied together by the tie bar 17. The tie bars 10,16, and 17 are, as will be described later, cut off by punching(indicated as hatched areas H1 and H2 in FIGS. 6 and 9).

FIG. 8 shows the state in which the photodetector element 1 and the IC 2for processing the signal therefrom are fixed on the element mount frame9 with adhesive. As the adhesive here, both an insulating type and aconductive type are used as necessary. The photodetector element 1 andthe IC 2 are connected together by a wire W1 for signal extraction. Thephotodetector element 1 and the element mount frame 9 are connectedtogether by a wire W2 for grounding. The IC 2 and the power supply (Vcc)frame 11 are connected together by a wire W3 for power supply. The IC 2and the signal output (Vout) frame 12 are connected together by a wireW4 for signal output. The IC 2, the fitting frame 8, and the elementmount frame 9 are connected together by wires W5, W6, and W7 forgrounding. The fitting frame 8 and the element mount frame 9 areconnected together by a wire W8 for grounding.

After these wires are strung, as shown in FIG. 9, the tying portion 13is bent so that the shielding frame 15 covers the element mount frame 9.As indicated by broken lines in FIGS. 7 and 8, the tying portion 13 hastwo bending lines inscribed thereon at a predetermined interval so thatit can be easily bent into a square-cornered C-like shape. The stressresulting from this bending spreads via the tying portion 13 to thefitting frame 8, but not further to the element mount frame 9 thanks tothe gap 5 left between the fitting frame 8 and the element mount frame9. That is, the stress that acts on the main frame 7 when the tyingportion 13 is bent is alleviated by the gap 5, which thereby shuts offthe spreading of the stress to the element mount frame 9.

In the state with the tying portion 13 bent as shown in FIG. 9, thewindow 14 of the shielding frame 15 overlaps the photodetector element1, permitting light to strike it. The photodetector element 1 is, exceptwhere it receives light, covered by the shielding frame 15. Moreover,the shielding frame 15 covers the greater part of the IC 2. Thus, the IC2 can process the signal from the photodetector element 1 under theshield provided by the shielding frame 15. Hence, even when the signalis faint, it is unlikely to be influenced by electromagnetic noise.

Subsequently, along lines S1 and S2 shown in FIG. 9, the leads L1 to L4are bent toward the rear face of the molding resin 3. FIG. 3 shows thestate of the frame after the bending of the leads, as seen from infront. The stringing of the wires and the bending of the leads may beperformed in reverse order, in which case first the leads L1 to L4 arebent and then the photodetector element 1 and the IC 2 are fixed,followed by the stringing of the wires.

Next, the leadframe is put in a molding frame filled with uncured resin,with the photodetector element 1 and the IC 2 facing down. When theresin cures, it forms the rectangular molding resin 3. The molding resin3 holds the individual frames at regular intervals. This increases themechanical strength of the photodetector module M1, and in additionmakes it free from a change in the angle of the photodetector element 1.

Thereafter, the tie bars B and the tie bars 10, 16, and 17 are cut offin the hatched areas H1 and H2 shown in FIGS. 6 and 9. Now, thefabrication of the photodetector module M1 shown in FIGS. 1 to 5 iscomplete. The fitting frame 8 and the element mount frame 9 are cutapart from each other, but their relative positions are fixed by themolding resin 3, and their electrical connection is secured by the wireW8.

The element mount frame 9 is cut apart from the other frames. Thedestination of the wire W8 may be so changed that it is electricallyconnected to a frame other than the fitting frame 8.

In this embodiment, the element mount frame 9 and the fitting frame 8are cut apart from each other. Alternatively, the tie bars 10, 16, and17 may be left uncut so that the element mount frame 9 and the fittingframe 8 remain tied together by the tie bars 10, 16, and 17.Specifically, they are cut off only in the hatched area H1 shown in FIG.9, and are left in the hatched area H2. This permits the element mountframe 9 and the fitting frame 8 to remain tied together by the tie bars10, 16, and 17. This helps increase the mechanical strength of theelement mount frame 9 and the fitting frame 8, and also helps save thetrouble of securing electrical connection with the wire W8.

With the photodetector module M1 structured as described above, when theleads L1 to L4 are inserted in holes formed in a mount circuit board andfixed thereto, the photodetective surface lies parallel to the mountcircuit board surface. When the photodetector module M1 receives lightshone from a direction perpendicular to the mount circuit board surface,it produces a signal.

Next, the photodetector module of a second embodiment of the inventionwill be described with reference to FIGS. 10 to 18. The followingdescription places emphasis on differences from the first embodiment.

FIG. 10 is a perspective view of the photodetector module of the secondembodiment, FIG. 11 is a front view, FIG. 12 is a front view with themolding resin removed, FIG. 13 is a side view, and FIG. 14 is a bottomview.

Like the photodetector module M1, a photodetector module M2 has aphotodetector element 1 and, as a circuit for processing the signaltherefrom, an IC 2 both sealed in a rectangular block of molding resin3. From the rear face of the molding resin 3 protrude five leads L1 toL5. The leads L1 to L5 are formed by bending parts of a leadframe F2,which will be described later.

Next, with reference to the FIGS. 15 to 18, which show the leadframe,the structure of the photodetector module M2 will be described alongwith the fabrication procedure thereof. FIG. 15 is a plan view of theleadframe, FIG. 16 is a plan view of the leadframe showing a portionthereof corresponding to a single photodetector module, FIG. 17 is aplan view of the leadframe as observed at one stage in the course of theassembly thereof, and FIG. 18 is a plan view of the leadframe asobserved at another stage, different from the one shown in FIG. 17, inthe course of the assembly thereof.

First, a leadframe FF as shown in FIG. 15 is prepared. FIG. 16 shows theshape of the leadframe F2 that is used in a single photodetector module.

As shown in FIG. 16, along one of the longer sides of the molding resin3 extends an elongate fitting frame 8, and from both ends thereofprotrude the leads L1 and L2. The leads L1 and L2 are used forconnection to the ground potential (GND).

The fitting frame 8, along with an element mount frame 9 laid beside itthat has a comparatively large area, forms a main frame 7. In the mainframe 7, between the fitting frame 8 and the element mount frame 9, agap 5 is formed in the shape of an elongate groove or cut. At both endsof the gap 5 are laid tie bars 10, 16, and 17 that tie the element mountframe 9 and the fitting frame 8 together.

Along the other of the longer sides of the molding resin 3 extends anelongate grounding frame 88, and from one end thereof protrudes the leadL3. The other end of the grounding frame 88 connects to the elementmount frame 9. Likewise, along the other of the longer sides of themolding resin 3 extends a power supply frame 11, and from one endthereof protrudes the lead L4. Between the fitting frame 8 and the powersupply frame 11 is laid a signal output frame 12, from one end of whichprotrudes the lead L5. The other end of the power supply frame 11 andthe other end of the signal output frame 12 both reach close to theelement mount frame 9.

In a position symmetric with the element mount frame 9 about the fittingframe 8, a shielding frame 15 is formed that has a window 14 formedtherein and that has a comparatively large area. The shielding frame 15is tied, via a tying portion 13, to a middle portion of the fittingframe 8.

The leads L1 and L3 are tied together by the tie bar 16, and the leadsL2, L5, and L4 are tied together by the tie bar 17. The tie bars 10, 16,and 17 are, as will be described later, cut off by punching (indicatedas hatched areas H1 and H2 in FIGS. 15 and 18).

FIG. 17 shows the state in which the photodetector element 1 and the IC2 for processing the signal therefrom are fixed on the element mountframe 9 with adhesive and the wires W1 and W8 are strung. After thewires are strung, as shown in FIG. 18, the tying portion 13 is bent sothat the shielding frame 15 covers the element mount frame 9.Subsequently, along lines S1 and S2 shown in FIG. 18, the leads L1 to L5are bent toward the rear face of the molding resin 3. FIG. 12 shows thestate of the frame after the bending of the leads, as seen from infront.

Next, the leadframe is put in a molding frame filled with uncured resin,with the photodetector element 1 and the IC 2 facing down. When theresin cures, it forms the rectangular molding resin 3. The molding resin3 holds the individual frames at regular intervals. This increases themechanical strength of the photodetector module M1, and in additionmakes it free from a change in the angle of the photodetector element 1.

Thereafter, the tie bars B and the tie bars 10, 16, and 17 are cut offin the hatched areas H1 and H2 shown in FIGS. 15 and 18. Now, thefabrication of the photodetector module M2 shown in FIGS. 10 to 14 iscomplete. The fitting frame 8 and the element mount frame 9 are cutapart from each other, but their relative positions are fixed by themolding resin 3, and their electrical connection is secured by the wire8. The element mount frame 9 is fed with the ground potential via thelead L3, or via the lead L1 (L2) and the wire W8.

The tie bars 10, 16, and 17 may be left uncut so that the element mountframe 9 and the fitting frame 8 remain tied together by the tie bars 10,16, and 17. Specifically, they are cut off only in the hatched area H1shown in FIG. 18, and are left in the hatched area H2. This permits theelement mount frame 9 and the fitting frame 8 to remain tied together bythe tie bars 10, 16, and 17. This helps increase the mechanical strengthof the element mount frame 9 and the fitting frame 8, and also helpssave the trouble of securing electrical connection with the wire W8.

The photodetector module M2 structured as described above is mounted ona mount circuit board in a manner similar to that by which thephotodetector module M1 is mounted.

With this photodetector module M2, the leads L2, L5, and L4, which arebent so as to protrude from the rear face of the molding resin 3, can bebent once again at a right angle so as to run in the direction oppositeto where the leads L1 and L3 are located. This permits the leads L2, L5,and L4 to protrude from the bottom face of the molding resin 3 parallelto the rear face thereof. When the leads L2, L5, and L4 in this stateare inserted into holes formed in the mount circuit board and fixedthereto, the photodetective surface of the photodetector module M2 liesperpendicular to the mount circuit board surface. When the photodetectormodule 2 receives light shone from a direction parallel to the mountcircuit board surface, it produces a signal. When only three of theleads are connected in this way, the unused leads L1 and L3 may be cutoff at the rear face of the molding resin 3.

In the first and second embodiments, the element mount frame 9 and thefitting frame 8 are kept at identical potentials. Alternatively, theelement mount frame 9 and the fitting frame 8 may be kept at differentpotentials, and examples of such structures will be described below as athird and a fourth embodiment of the invention. Note that the thirdembodiment is a slightly modified version of the first embodiment, whichbasically addresses a four-lead structure, and the fourth embodiment isa slightly modified version of the second embodiment, which basicallyaddresses a five-lead structure. Accordingly, the following descriptionplaces emphasis on differences from the respective basic structures.

The photodetector module of the third embodiment of the invention isshown in FIG. 19. FIG. 19 is a plan view showing the leadframe asobserved at one stage in the course of the assembly thereof. From bothends of an element mount frame 9 protrude leads L1 and L2. The leads L1and L2 are used for connection to the ground potential (GND). Thus, theelement mount frame 9 functions as a grounding frame.

The element mount frame 9, along with a fitting frame 8 laid beside it,forms a main frame 7. In the main frame 7, between the fitting frame 8and the element mount frame 9, a gap 5 is formed in the shape of anelongate groove or cut. At both ends of the gap 5 are laid tie bars 16and 17 that tie the element mount frame 9 and the fitting frame 8together. The element mount frame 9 is so long as to cover the entireinterval between the tie bars 16 and 17. That is, the element mountframe 9 is nearly as long as the gap 5. The tie bars 16 and 17 are cutoff by punching in the hatched area H1 shown in FIG. 19.

From one end of the fitting frame 8 protrudes a lead L3. The lead L3 isused for connection to supplied power (Vcc). Beside the element mountframe 9 extends a signal output (Vout) frame 12, from one end of whichprotrudes a lead L4.

In a position symmetric with the element mount frame 9 about the fittingframe 8, a shielding frame 15 is formed that has a window 14 formedtherein. The shielding frame 15 is tied, via a tying portion 13, to amiddle portion of the fitting frame 8. Between the fitting frame 8 andthe shielding frame 15, except in the tying portion 13, an elongate cut6 is formed to separate the fitting frame 8 and the shielding frame 15from each other. This helps give a smaller width to the tying portion13, which functions as the very portion that is bent.

FIG. 19 shows the state in which the photodetector element 1 and the IC2 for processing the signal therefrom are fixed on the element mountframe 9 with adhesive. As the adhesive here, both an insulating type anda conductive type are used as necessary. The photodetector element 1 andthe IC 2 are connected together by a wire W1 for signal extraction. Thephotodetector element 1 and the element mount frame 9 are connectedtogether by a wire W2 for grounding. The IC 2 and the fitting frame 8are connected together by a wire W3 for power supply. The IC 2 and thesignal output frame 12 are connected together by a wire W4 for signaloutput. The IC 2 and the element mount frame 9 are connected together bywires W5, W6, W7, and W8 for grounding.

After the wires are strung, in the same manner as shown in FIG. 9, thetying portion 13 is bent so that the shielding frame 15 covers theelement mount frame 9. Subsequently, the leads L1 to L4 are bent towardthe rear face of the molding resin 3. Next, the leadframe is put in amolding frame filled with uncured resin, with the photodetector element1 and the IC 2 facing down. When the resin cures, it forms molding resinlike the molding resin 3 shown in FIG. 1. The molding resin holds theindividual frames at regular intervals.

Thereafter, the tie bars are cut off, and now the fabrication of aphotodetector module having an outward appearance similar to that of thephotodetector module M1 of the first embodiment is complete. The fittingframe 8 and the element mount frame 9 are cut apart from each other, buttheir relative positions are fixed by the molding resin.

The photodetector module of the fourth embodiment of the invention isshown in FIG. 20. FIG. 20 is a plan view showing the leadframe asobserved at one stage in the course of the assembly thereof. From bothends of an element mount frame 9 protrude leads L1 and L2. The leads L1and L2 are used for connection to the ground potential (GND). Thus, theelement mount frame 9 functions as a grounding frame.

The element mount frame 9, along with a fitting frame 8 laid beside it,forms a main frame 7. In the main frame 7, between the fitting frame 8and the element mount frame 9, a gap 5 is formed in the shape of anelongate groove or cut. At both ends of the gap 5 are laid tie bars 16and 17 that tie the element mount frame 9 and the fitting frame 8together. The tie bars 16 and 17 are cut off by punching in the hatchedarea H1 shown in FIG. 20.

A lead L3 is laid beside the lead L1. The lead L3 is connected, via atie bar 10 and the tie bar 16, to the element mount frame 9. The leadL3, like the leads L1 and L2, is used for connection to the groundpotential (GND). From one end of the fitting frame 8 protrudes a leadL4. The lead L4 is used for connection to the supplied power (Vcc).Between the element mount frame 9 and the fitting frame 8 extends asignal output (Vout) frame 12, from one end of which protrudes a leadL5.

In a position symmetric with the element mount frame 9 about the fittingframe 8, a shielding frame 15 is formed that has a window 14 formedtherein. The shielding frame 15 is tied, via a tying portion 13, to amiddle portion of the fitting frame 8. The fitting frame 8 is, in aportion thereof near the tying portion 13, shaped nearly symmetricallyabout the tying portion 13. Thus, when the tying portion 13 is bent, theresulting stress is equally distributed between both sides of the tyingportion 13. Between the fitting frame 8 and the shielding frame 15,except in the tying portion 13, an elongate cut 6 is formed to separatethe fitting frame 8 and the shielding frame 15 from each other. Thishelps give a smaller width to the tying portion 13, which functions asthe very portion that is bent.

FIG. 20 shows the state in which the photodetector element 1 and the IC2 for processing the signal therefrom are fixed on the element mountframe 9 with adhesive. As the adhesive here, both an insulating type anda conductive type are used as necessary. The photodetector element 1 andthe IC 2 are connected together by a wire W1 for signal extraction. Thephotodetector element 1 and the element mount frame 9 are connectedtogether by a wire W2 for grounding. The IC 2 and the fitting frame 8are connected together by a wire W3 for power supply. The IC 2 and thesignal output frame 12 are connected together by a wire W4 for signaloutput. The IC 2 and the element mount frame 9 are connected together bywires W5, W6, W7, and W8 for grounding.

After the wires are strung, in the same manner as shown in FIG. 18, thetying portion 13 is bent so that the shielding frame 15 covers theelement mount frame 9. Subsequently, the leads L1 to L5 are bent towardthe rear face of the molding resin 3. Next, the leadframe is put in amolding frame filled with uncured resin, with the photodetector element1 and the IC 2 facing down. When the resin cures, it forms molding resinlike the molding resin 3 shown in FIG. 10. The molding resin holds theindividual frames at regular intervals.

Thereafter, the tie bars are cut off, and now the fabrication of aphotodetector module having an outward appearance similar to that of thephotodetector module M2 of the second embodiment is complete. Thefitting frame 8 and the element mount frame 9 are cut apart from eachother, but their relative positions are fixed by the molding resin.

In the third and fourth embodiments, the shielding frame 15, which iskept at the supplied power potential (a potential different from theground potential), shuts off electromagnetic noise.

It should be understood that the invention may be carried out in anyother manner than specifically described above as embodiments, and thatmany modifications and variations are possible within the scope andspirit of the invention.

INDUSTRIAL APPLICABILITY

The present invention find wide application in photodetector modules ofthe type that has a photodetector element fixed on a leadframe andsealed in a resin molding.

1. A leadframe comprising an element mount frame, a fitting frame thatis laid beside the element mount frame with a gap left in between, and ashielding frame that is tied via a tying portion to the fitting frameand that can be brought into such a state as to cover the element mountframe.
 2. The leadframe of claim 1, wherein the tying portion isprovided at both ends of the gap.
 3. The leadframe of claim 1, whereinthe element mount frame and the fitting frame are separate.
 4. Theleadframe of one of claim 1, wherein the fitting frame is, in a portionthereof near the tying portion, shaped symmetrically about the tyingportion.
 5. A photodetector module comprising a photodetector element,an element mount frame on which the photodetector element is mounted, afitting frame that is laid beside the element mount frame with a gapleft in between, a shielding frame that is tied via a tying portion tothe fitting frame and that can be brought into such a state as to coverthe element mount frame, and molding resin in which the element mountframe and the fitting frame are sealed.
 6. The photodetector module ofclaim 5, wherein the element mount frame and the shielding frame arekept at an equal potential.
 7. The photodetector module of claim 5,wherein the element mount frame and the shielding frame are kept atdifferent potentials.
 8. The photodetector module of claim 5, wherein acircuit element that processes a signal from the photodetector elementis mounted on the element mount frame.
 9. The photodetector module ofclaim 5, wherein the element mount frame and the gap have nearly equallengths.